Projectile with shaped charge and point initiating fuze



Dec. 21, 1954 K. LILJEGREN PROJECTILE WITH SHAPED CHARGE AND POINTINITIATING FUZE I Filed Feb. 14, 1944 3 Sheets-Sheet l gwumn/bo'n LY LEK L ILJEEIREN,

MWWM L. K. LILJEGREN 2,697,400

3 Sheets-Sheet 2 PROJECTILE WITH SHAPED CHARGE AND POINT INITIATINGFUZE.

MN, 4 \M W 1% r y MK am No mm W m r 0 M1 N m R Q A m kwv M m I 1 9 W Mvb K 9 9v uw w m N. m L mm AA 9%. QR m N m Hm ma mu m mm M \M 90 W 9o EQ Q mob in i mx a K m mm \W m5 m $9 b9 9? on Dec. 21, 1954 Filed Feb.14, 1944 Ml H Dec. 21, 1954 L. K. LILJEGREN PROJECTILE WITH SHAPEDCHARGE AND POINT INITIATING FUZE Filed Feb. 14, 1944 3 Sheets-Sheet 5 mmw w .om .MVY l .n. m Hrmw mm, 3

A W A c WWI Ilium United States Patent i thee 2,697,400 Patented Dec.21, 1954 PROJECTILE WITH SHAPED CHARGE AND PDINT INITIATING FUZE Lyle K.Liljegren, Pasadena, Calif., assignor to the United States of America asrepresented by the Secretary of War Application February 14, 1944,Serial No. 522,290

16 Claims. (Cl. 192-56) (Granted under Title 35, U. S. Code (1952), see.266) The invention described herein may be manufactured and used by orfor the Government for governmental purposes without the payment to meof any royalty thereon.

This invention relates to fuses for pro ectiles, and has for an objectto effect an improvement in the construction and arrangement of partswhereby the device w1ll be simplified and its action made more simpleand effective while at the same time retaining the advantages .ofsafety.

It is an important object to reduce the number of parts required in thefuse, and to also avoid the use of extremely small centrifugally movedparts to the end that the possibility of relatively high variables offriction in proportions to mass of such elements, and the possibilitythat the friction :factor may exceed the moment of inertia in such partswill be largely if not entirely obviated.

It is an aim to offer a point detonated base fuse construction of novelform, in which will be overcome objections to prior base fuses, such asirregularities or uncertainties due to varying sensitivity of the fuseas a Whole, varying velocities, and varying retardation of the Windshield, and particularly variation of deceleration after impact, duringcollapse of the wind shield.

A further aim of the invention is to enable its use in conventionalshell body construction, wind shield, hollow cone and main explosivecharge.

A still further object is to provide a novel form of centrifugallyoperated arming device of novel construction including the usual safetyfrom accidental arming by lateral shocks accidentally suffered by theprojectiles, or accidental operation of the point detonator.

A further important aim is to present a novel construction for effectingthe detonation of a base booster charge by a point-mounted primer fusewhich includes a shaped charge detonatable upon impact and upon collapseof the projectile wind shield to detonate the booster charge by means ofa kinetic element, viz. a

blast effect or pellet, released by the detonated primer and projectedrearwardly in timed relation to the forward speed of the projectile toinitiate action of a base booster detonator.

A further aim is to give a novel connection between base and pointstructure in such a fuse to the end that automatic compensation iseffected for variation from standard dimensions of the various partslongitudinally of the shell and for variation in spacing of the base andpoint elements of the device, both as to assembly of the round inmanufacture and in the operative and safety functioning of the parts.

Additional objects, advantages and features of invention reside in theconstruction, arrangement and combination of parts involved in theembodiment of the invention as will appear and be understood from thefollowing description and accompanying drawings, wherein:

Fig. l is a longitudinal section of an armor penetrating or demolitionprojectile, in which my invention is incorporated;

Fig. 2 is a transverse section taken on line 2-2 of Figure 4;

'Fig. 3 is a fragmentary longitudinal section taken on line 3-3 ofFigure l.

'4 is a section on the line 4?4 of Fig. 1. Fig. 5 is a section on theline 5-5 of Figure 4,

Figure 6 is a view corresponding to Figure 4 with slide moved to rightand with booster detonator on longitudinal axis of projectile.

Figure 7 is a fragmentary longitudinal section taken on line 7--7 ofFigure 4.

Fig. 8 is a fragmentary longitudinal section of a modification of thetube for transmitting the kinetic element from the point located fuse tothe base detonator.

Fig. 9 is a detail of a modified tube.

Fig. 10 is a detail of a further modification.

Fig. 11 is a sectional view of a modification of the base fuse.

Referring to the drawings, there is illustrated a projectile built toutilize the Munroe efiect in penetrating armor or concrete structures,or for other purposes, and comprising a shell body 15 of conventionalform, the ogival portion of which is a frusto conical wind shield 16 ofconventional structure mounted on the end of the shell, conical elementsof the shield being tangent to the short ogival curve .17. The shell hasa bore or cavity 18 of cylindrical form throughout, the face of which isrelieved at each end of the projectile to afford circumferentialshoulders 19 and 20 at the front and rear respectively, the shoulder 20being somewhat further from the rear end of the body than the shoulderi9 is from the forward end. The relieved portions are interiorlythreaded. A hollow cone 21 is provided, formed of thin material, with abase flange 22 set against the shoulder 19 and held thereto by anexteriorly threaded nipple 23 screwed into the interiorly threadedforward end of the shell body and extending forwardly therefrom adistance. An interior .base ring 24 of the wind shield is screwed ontothis forward part of the nipple so that the shield abuts snugly theforward end of the shell body.

A point detonator or fuse 25 :is mounted at the .apex of the windshield, consisting of a heavy walled metal body 26 set and secured in asuitable concentric opening in the shield, with a broad point 26' and areduced tubular stem 27 extending axially into the space within thewindshield.

A circular coaxial recess 28 is formed in the point 26, open forwardlythrough the end of the point and of such size that a relatively thinwall 29 is left around the recess, collapsible by target impact. A smallaxial bore 30 is formed from the bottom of the recess inwardly,communicating with a larger primer bore 31 rearwardly thereof, in whicha cased detonating primer 32 formed as a rearwardly opening shapedcharge having a thin metal liner 32a is secured by means of a bushing 33screwed into an enlargement of the bore behind the primer. A tube 35 isset in the apex of the cone, extending therefrom to a base fuse to bedescribed. In practice the tube has been formed with an externaldiameter of three eighths of an inch and an internal diameter of fivesixteenths of an inch or more. The tube extends through the vertex ofthe cone 21, which is suitably necked therearound, and formscommunication axially between the interior of the cone and the base fuseas will appear.

The shaped charge with, or produces from its cup materialor liner 32a ondetonation, a pellet or slug, which is pro elled rearwardly throughspace to and through the tube to detonate the base fuse. It iscontemplated also that the detonator will produce a Munroe efiect whichwill act through the tube 35 to detonate the base fuse. In the smallbore 30 there is slidab'le a firing pin 36 having a mushroom head 37 inthe recess 28 normally close to the extremity of the wall 29, and in thewall there is set a thin frangible or otherwise impact-yielding wind anddust guard plate 38, which may be of lead or gildingmetal.

The pin 36 is of such length that its extremity is within the :bore 30initially and retained in this position by a tubular support 39frangible or collapsible under a predetermined force acting on the head37 of the pin. This support 39 is set loosely, Or slightly frjctioriallyengaged around the pin and resting on the bottom of the recess 28 andagainst the head 37 of the pin.

The base fuse 4% consists in this instance of a substanprimer 32 in oneform is provided tially cylindrical body 41 of steel, and for a six inchshell has been made approximately two inches in diameter, its lengthbeing somewhat greater. In addition it is formed with a threaded tenon42 at the rear and an axially bored gland neck 43 forwardly. The tenonis screwed into a circular base plate 44, which is set against theshoulder with an interposed gasket 44. and so held by the base plug 45screwed into the threaded enlarged rear end portion of the bore orcavity of the body 15. In this way the body 41 is supportedconcentrically in the projectile with the gland neck 43 receivingtherein slidably a small portion of the end of the tube 35. The rearextremity of the tube may be closed with a thin weak septum 47 in theform of lead foil across the opening through the tube. The rear end edgeof the tube is rounded at the outer side, as at 48. A relatively largebooster chamber 49 is formed at the rear part of the body 41. Thisconsists of a simple cylindrical diametrical bore opening flush throughopposite sides of the body 41. Its rear side is spaced slightly from thebase plate 44 and it has a diameter of somewhat more than one inch inthe size of fuse mentioned.

The bore 50 in the neck 43 extends into the body 41 a distance but stopsshort of the chamber 49. A cylindrical recess 51 is bored in the side ofthe body 41 thereof and stopping short of the bore 50 so that anintervening partial wall portion 52 is left at the bottom of the recess.A smaller bore 53 forms a transverse continuation of recess 51 stoppingat its inner end a distance from the periphery of the body and bore 53are aligned facing the chamber 49, and a flash port 54 coaxial with thebody 41 and bore 50 is formed through the material intervening betweenthe booster chamber and bore 53. Diametrical detent guide passages 55are bored through the body 41 on an axis normal to a plane including theaxes of the body and bore 53, of slightly less diameter than the bore 50and intersecting the bore 53. Around the body 41 a circumferentialnarrow groove 56 is formed in a plane including the axis of the passages55 and intersecting each end of the latter and the recess 51.

In the bore 53 there is engaged an arming slider 57, including acylindrical bar or stem 58 fitted slidably in the bore 53 and having aneccentric circular weight head 59 fitting slidably in the recess 51normally at the bottom of the latter, and of such thickness radially ofthe fuse body as to permit necessary sliding movement of the slider inthe bore 53 and recess 51. In the forward side of the slider stem 58,there is formed a transverse cam recess 60 having flat sides slopingdivergently in opposite directions longitudinally of the stem and at anacute angle to the axis of the stem, from a central line of maximumdepth of the recess to the periphery of the stem 58. The depth of thisrecess and the disposition of 41. The lower faces of the recess itssides is such that the recess will include a geometrical projection ofthe passages 55 across the bore 53. The recess 6% will be termed the camface 61. Slidable in the passages 55 there are respective detentcentrifugals 62 having at their inner ends reduced normally meetingflatend pins 63. Slidable in the inner or rearward part of the bore 50there is a slider lock 64, consisting of a cylindrical block havingopposite bevelled rear end faces conforming and normally fitting to thesides of the recess 60. The lock 64 has formed in opposite sides smallapertures 65 inwhich the pins 63 engage initially.

The plns initially close the passage 66 through the lock 64. Thecentrifugals 62 are initially held in detent positlon as in Fig. 5 bymeans of a U-shaped spring 67 set in the groove 56, the ends of 'thespring bearing on the outer ends of the centrifugals, which extendinitially into the groove 56 slightly and are movable outwardly to theper phery of the fuse body, clearing the lock 64. The spring has areentrant bight portion 68 bowed inwardly so as to rest against thebottom of the groove 56, While its arms 69 lie in the groove and acrossthe ends of the passages 55 and centrifugals 62. The shoulders 68' ofthe blght are at the periphery of the body 41 and retained there by afuse case 70 to be subsequently described.

I in the extreme inner end portion of the slider 57 there 1s a detonatorreceiving opening or cup 69 extending from the forward side nearlythrough the stem 58 but having a reduced opening through the rear sideof the stem. A shoulder 71 is thus provided at the rear end of theopening against which there is seated a detonator 72 of conventionalkind for the purposes intended. When the slider is at the outer limit ofits movement the detenator 72 is in line with the flash port 54 at therear and with the bore 50 at its forward side. The bore 50 is slightlyrelieved at its outer part near the end of the tube 35, forming ashoulder there, and a cup 73 of gilding metal is set against theshoulder spacing the end of the tube 35. The material of the cup isquite thin, material such as gilding metal having a thickness of.OOZ-inch having been employed in one embodiment of the inventron.

The body of the fuse is snugly enclosed by a cylindrical case 70 of softsteel in the form of a cup having a flanged opening through its innerpart to receive the neck 43 therethrough, the flange 74 lying flatagainst the inner end of the body 41. The lip 75 of the case is crimpedinto a base groove 71 of the body 41 immediately adjacent the base plate44. In this way the fuse is securely enclosed and may be made waterproofwith application of shellac or other suitable material under or at theedges of the casing.

In the base fuse, for operation with the point detonator described, thedetonator 72 may have in the forward part a material 76 such as leadazide or fulminate of mercury suitable for detonation by blastpropagation, penetration or concussion, as by a blast, a firing pin orthe pellet before mentioned, and at the rear part may have an explosive77 such as tetryl. Usual retaining and sealing discs may be used, one ateach end of the detonator as customary.

In the chamber 49 a booster 79 such as tetryl is packed, retained by thecase 70, and in the large cavity of the shell around the base fuse andrearwardly of the cone 21 a charge 80 of a suitable high explosive isprovided.

In the manufacture of my fuse, it is an advantage that the cavities inthe body may be produced by simple and very few drill operations as thetransverse bores have but two directions and the whole may be drilled intwo gang operations. The bore 50 and flash port 54 may be produced inone operation. Also the slide and centrifugals are correspondinglysimple and free from complications in securing good working fits andfunctioning. The surfaces of the various parts may be coated withprotective noncorrosive material, if desired, and in practice a cadmiumcoating has been employed, which has the further advantage of minimizingfriction.

My invention also enables the centrifugals to be made of good bulk inorder to attain adequate mass for good working qualities, and readycalculation of the forces developed, to readily determine the necessarystrength in the spring, as well as reducing the factor of fllCllOIl inproportion to the force of the spring and centrifugal force in thecentrifugals 62 as well as in the slider 57, and lock 64.

Assembly and loading of the projectile My invention also simplifies andfacilitates assembly of the parts of the projectile and loading thereofwith its main charge.

The shell, cone, be assembled before loading,

windshield and point detonator may or, for safety, the point detonatoromitted until after loading and then introduced.

The base fuse may be assembled on its base plate and positioned afterloading of the shell with its main or bursting charge. The latter hasbeen produced in a plastic state and its lower part moulded to afford arecess conforming to the shape and location of the base fuse whenfinally positioned. In the placing of the charge with such form, therear end of the tube 35 projects axially into the smaller inner part ofthe recess of the charge, and the neck 43 of the fuse body engagesslidingly around this tube end as the base fuze is inserted in the baseof the shell and charge, and the base plate 44 brought to rest againstthe gasket 44 and shoulder 20. The shell is then closed with the baseplug '45, which holds the parts rigidly secured in their properpositions.

Fuse action Qn firing, during lmtlal propulsion movement of theprojectile in the gun, the parts remain in the same positions, and theyremain so until axial acceleration of the projectile in engagement withthe rifling of the gun produces the rate of rotation of the projectileat which it has been predetermined as desirable for the centrifugals 62to overcome the force of the spring 67. This rate may be in theneighborhood of 2000 revolutions per minute, and may be'more or lessdepending upon the total twist of the rifling in the gun, and/or themaximum rate of propulsion produced as the projectile leaves the muzzleof the gun. While the safety of the fuze is greater before action of thecentrifugals, the purpose of this limitation of their action is notentirely to delay arming of the fuse, during movement in the gun, aswill appear, but will be effective in preventing arming if a mistake inthe selection or amount of the propelling charge is made which resultsin too little speed in the projectile and so an explosion too near thegun will not occur. Also safety in case of accidental lateral shock isattained.

After the centrifugals have moved out of engagement with the lock, thelatter still remains firmly pressed against the cam face 61 by set backor inertia of the lock acting rearwardly under forward acceleration ofthe projectile still occurring in the gun. This acceleration continuesuntil the projectile leaves the muzzle. As soon as the projectile leavesthe gun nuzzle the forces of setback cease, and the projectile continuesto accelerate until the designed speed to attain the predeterminedcentrifugal force is achieved, whereupon slider 57 will move outwardlydisplacing the lock 64 forwardly from the cam recess 60 by cammingaction of the face 61 against the rear end of the lock. The slider thusreaches its armed position, at the outermost limit of movement, with thedetonator 72 in line with the passage through the lock 64 and with theflash port 54 behind which the booster charge 79 is exposed.

On impact of the projectile with the target, the head 37 of the firingpin of the point fuse is operated, driving the pin 36 into the primerand detonating the same. The wall portion 29 may collapse at the sametime, but detonation at 25 will occur before any material impedance orobstruction occurs in the path of the pin or in the passage to orthrough the tube 35. Explosion of the primer 32 results in projection ofa pellet or blast, or

both, from the point detonator rearwardly through the tube 35, throughthe foil 47 and cup 73 in the bore 50 and against the sensitive material76, which immediately fires the high explosive primer powder 77. Thisproduces a flash through the port 54, exploding the booster 79 andsetting off the main charge 80 in the projectile.

During the described occurrences, incident to impact on the target,elements or factors of time and movement will have been manifest,including the time and movement occurring after impact during which thewindshield is collapsing, and the mouth of the shell and cone are movinginto position for best utilization of the Munroe effect. The nature andamount of the explosive in the primer 32 and the weight of the pelletare selected relative to the force of impact of the projectile, itsforward speed, and the rate of collapse of the windshield, so that themain explosive charge is detonated at the proper stand-off distance ofthe shaped charge from the target, to give maximum penetration andoptimum explosive effect.

These elements are so coordinated that the explosion of the main chargewill occur as, or about when the mouth of the shell body reaches thematerial engaged by the point and by which initial detonation at thepoint is caused. The time of movement of the pellet or blast to thedetonator 72 will compensate for the time of movement of the shell bodythe length of the windshield, including retardation involved ineffecting the collapse or telescoping of the latter.

In consequence, the blast of the main charge will be delivered againstthe target with the maximum practical utilization of the energy releasedin its application by the Munroe efiFect method.

It should be appreciated that while there may be some variation in thetime required for complete collapse of the windshield due to variouscauses including longer or shorter deceleration incident to longer orshorter range, or variations in wind resistance, etc. the time willnevertheless vary within a small degree. Consequently, by selecting aprimer for the point detonator which will project its detonating effectto the detonator 72 in a period of time which is a mean of those whichexperience show may be required under extremes of variance in theretardance to be expected, there will be an automatic compensation inthe practical functioning of the organization by departures in eitherdirection from such mean requirement. That is to say, where thecommunicated detonation is ideal for a given speed of the shell incollapse of the windshield the transmission from the point to the basewill involve a time x. If the shell engages the target at a greaterspeed, the convergent movement of the base and the projected detonatingwave or pellet will be correspondingly more rapid, shortening the timeof travel of the communicated effect, to accord with the earlier arrivalof the shell cavity in good operative relation to the target body.correspondingly, if the speed of the projectile is slower than thechosen mean projectile speed, the convergence of the base fuse and thepropagated element from the point fuse will be correspondingly slowerand delayed.

In the form of the invention, shown in Fig. 8, the bore in the stem 27of the point body is extended further and enlarged rearwardly of theprimer retaining bushing of the point structure, as at 28 and a tube 35engaged and secured therein which is extended rearwardly and into theneck 43 where it may be secured. The base and point structure mayotherwise be the same as before de scribed. In this form, the forwardpart or the whole length of the tube between the cone and stem 27' ofthe point is of a light weight meltable or quickly combustible material.Onernaterial suitable for the purpose is known as Pentalite. In anotherform the tube 84 may be metalsheathed tetryl as in Fig. 9. The sheathmay be on the interior, as at 85, as well as the exterior of the tube,as at 86. A lead sheath has been used. With the modification indicated,on detonation of the primer at the point, the blast with the Munroeeffect, or a projected part from the primer, will travel through thetube with great certainty effecting the detonation of the detonator 72.

Explosion of the main charge will destroy the tube 35' instantly. Theblast from the point primer will tend to ignite the tube 35', but suchignition will not occur until after communication of the necessaryconcussion to the rear detonator, or at least until after passage of thedense area of the Munroe wave or pellet or both, past the point ofignition and ahead of any propogation of ignition along or in thematerial of the tube. This applies particularly to the metal-sheathedtetryl the metal serving to delay the ignition and combustion of thetube.

On account of the great stresses set up in the body of the tube 35, 35and 84 when the projectile engages the target, due to inertia ofmomentum in the tube material, and to guard against possible breakage ofthe tube before completion of communication of the detonating effect tothe base detonator, I have shown in Fig. 8 an anchoring means on thebase fuse by which the tube is automatically connected to the base whenthe base fuse is put in place. In this instance the tube is thickened atits rear end portion and formed with a circumscribing groove 87 near itsrear extremity and its rear end is bevelled as at 88. The neck 43' andbore 50' are suitably enlarged to receive the enlarged end of the tube,and an interior groove 89 formed in the enlarged bore 50 arranged andproportioned to aline with the groove 87 when the tube end is inserted.A C-spring 90 of circular form, set initially in the groove 89, is of aradial cross sectional dlmension sufiicient to lie with portions in thegrooves when the latter are alined. The spring 90 has flat sides inparallel planes normal to the axis of the tube and neck, but is bevelledon its inner side so as to permit the end of the tube to be readilypushed through it when the base fuse is being put in place. Afterassembly the tube cannot be pulled from the neck 43, exceptdestructively, due to the engagement of the spring 90 therewith.

The construction of the safety and arming features in the base fuse ofmy invention are of such character as to be applicable to various formsof fuses, and in Figure 11 I have shown an adaptation of that part ofthe invention in the base fuse structure to use as an inertia base fuseof general application. Here, the booster chamber and charge, and theslider except 'centrifugals 62 as before described, are embodied in theidentical form and relation already described, and the rear portion ofthe body 41 of the fuse may be of similar form. The forward part,however, instead of having the reduced neck is extended the full size ofthe rear part. and a large bore 100 formed concentrically, opening. onthe forward end, from which a smaller bore openson the bore 53. A lookand, primer carrier 101 having an axial passage 102 therethrough isslidable in the large bore, having also a reduced hollow stem 103(through which the passage 102 continues) extending through the bore 55into the recess of the slider, this recess being of the same form asbefore, and having the inner cam face 61 acting against the end of thestem 103 in the same manner as it acts against the lock 64 in the firstconstruction.

The forward end of the bore is interiorly threaded and has screwedthereinto a closing plug 104, on the inner side. of which. there is afiring pin alined with the. passage 102 and adapted to enter the same onrelative forward movement of the lock 101. The inner rear end of thepassage 102, is formed with a stop shoulder or lip and against this isset a conventional primer 106 having a percussion material at its endtoward the pin 105. In the initial or safety position of the parts. asshown in Figure 11, the stem 103 being fully engaged in the recess 60,the primer is spaced from the pin slightly more than the depth of therecess 60 in the stemof the slider. As a safety for the detonator 106diametrically opposite centrifugals 107 may be mounted in suitablerecesses in the body 41' adjacent the forward end, of. the lock 101,held by a C-spring 108 in a groove 109 so as to operate in the samemanner as the centrifugals 62 or 62 which may be omitted. Thecentrifugals 107 have small pin portions extending through reducedopenings through the wall of the bore 100 and projecting only a shortdistance before the lock, so that the necessary radial movement forarming may be provided for in the material of the fuse body beside thebore.

The action of this fuse in the gun on firing is similar to that firstdescribed. The centrifugals 107 are thrown out after the projectilereaches a rotation rate sufiicient to overcome the force of the spring108, but the stem 103 of the lock 101 remains in the recess 60, opposingarming movement of the slide 57 under set back effect.

After the projectile leaves the gun, the slider operates centrifugally,as before moving the cup 69 into line with the port 54. The element 72in this particular cup may 75 be omitted if. desired for certain uses,or may be so composed as to constitute a delay button of relatively slowburningpowder, or may he a second percussion detonator. This cup 69 isat the same time alined with the passage 102 and detonator 106. Themovement of the slider moves the lock forwardly until the primer 106 isnear the pin 105, and on impact of the projectile with the target,inertia of the lock 101 carries it forward driving the primer. againstthe pin. The resulting flash through the rear end of the stem 55 willpass through the cup 69, if empty, and also the flash port 54, explodingthe booster charge 79.

If a delay button is incorporated in the cup 659 there will be acorrespondingly delayed ignition of the booster charge and if a seconddetonator is set in the cup there will be a consequent quickerdetonation of the booster.

As shown in Figure 10 l have embodied the Munroe effect more definitelyto act by propulsion of a detonating wave' or blast, by forming the baseof the cup 110 for the point detonator or primer with an extended anddeepened reentrant cone 111, and in such case the wall .material of thecone 111 may be much thinner than the usual cup base. It may also bemade of zinc, aluminum, or magnesium, or alloys, or a combustibleplastic, so as to'beconsumed ondetonation of the primer.

It is a further advantage of my invention that the arrangement of thecentrifugals 62, enables them to be located a greater distance from theaxis of the projectile than is usual; This has important advantages fromseveral aspects. Thus, it obviates liability of failure to operate dueto variations from manufacturing specifications as to mass anddimensions. And, perhaps most important. reduces or eliminates liabilityof failure of the centrifugals to clear the detonating train by reasonof yaw or rotation of the centrifugals eccentrically for any otherreason. Oftenthe axis of rotation is not/the axis of the projectile andif the center of gravity of the centrifugal is close to the projectileaxis, the moments of the centrifugals may have either reduced values oreven negative effects.

While I- have disclosed my invention with particularity in the bestembodiment developed at this time, it will be understood that: this isexemplary only and that modifications of construction, arrangement andcombination, substitution of materials and equivalents, mechanical orotherwise may be made without departing from the spirit of theinvention.

I claim:

1. in a projectile, an impact responsive primer located in the pointthereof for initiating action of. said projectile upon impact with atarget, said primer including a first rearwardly directed, shapedcharge, a second forwardly opening shaped charge in said projectileaxially separated from said first shaped charge, said first and secondshaped charges defining a, space which is free of intervening structure,detonating means at the base of said projectile for initiating action ofsaid second shaped charge, there being an axial passage formed in saidsecond; shaped charge and communicating with said detonating means, anda kinetic element responsive to the detonation of said first shapedcharge rearwardly projectible through said space and to and through saidaxial passage to initiate action of said detonating means.

2. In a projectile, an impact responsive primer located in the pointthereof for initiating action of said projectile upon impact with a,target, said primer including a first rearwardly directed. shapedcharge, a second forwardly opening shaped explosive charge in saidprojectile axially separated from said first shaped charge, said firstand second shaped, charges defining a space free of interveningstructure, detonating means at the base of said projectile forinitiating action of said. second shaped charge, and means, including anaxial elongated passage in said second shaped charge and intermediatesaid primer and said detonating. means, responsive to detonation of saidfirst shaped charge for initiating action of said. detonating means.

3. In a projectile, an impact responsive primer located in the pointthereof for initiating action of said projectile upon impact with atarget, said primer including a rearwardly directed first shaped chargeand a liner for said first charge forming a kinetic element, projectiblerear wardly by the blast propagated by said first shaped charge, asecond forwardly opening shaped explosive charge in said projectileaxially separated from said. primer, said primer and said second shapedcharge defining a space free of intervening structure, detonating meansat the base of said projectile responsive to impact of said kineticelement for setting off said second. shaped charge, said second shapedcharge having an axial passage formed therein providing an open path forsaid kinetic element between said first shaped charge and said detonatmgmeans.

4. In a projectile having a cylindrical body portion and afrusto-conical forwardly extending impact collapsible windshield securedto said body portion, an im pact detonatable primer in the nose of saidwindshield, said primer comprising an explosive having a smallrearwardly opening conical cavity forming a first shaped 1 charge, anexplosive charge in said body portion, said explosive charge having aforwardly opening large conical cavity forming a second shaped. charge,said windshield, said primer and said second shaped charge defining aspace free of intervening structure, a detonator in said body portionadjacent the base thereof for setting oif said explosive charge, saidexplosive charge in said. body portion having an elongated axial passageintermediate said base detonator and said primer, whereby said detonatoris responsive to the blast produced by said impact detonatable primertraversing through said space and to and through saidv axial passage toset off said explosive charge.

5. In a projectile having a cylindrical body portion. and a forwardlyextending frusto-conical impact collapsible windshield secured tosaidbody portion, an impact detonatable primer in the nose of saidWindshield comprising an explosive forming a first shaped charge, aliner for said first shaped charge forming a pellet when said primer isexploded, an explosive charge in said body portion, said explosivecharge having a forwardly opening large conical cavity forming a secondshaped charge, said windshield, said primer and said second shapedcharge defining'a space free of intervening structure, a detonator insaid body portion adjacent the base thereof for setting off of saidexplosive charge, said explosive charge having an elongated axialpassage intermediate said base detonator and said first shaped charge,whereby the blast from said first shaped charge on impact drives saidpellet reainvardly through said space and to and through said axialpassage to set-off said detonator.

6. A projectile comprising in combination a shell having a hollow frontend, a load of explosive located in said shell with its front facerearward of said hollow front end, said load of explosive being formedwith a cavity extending rearwardly from its front face, said cavityincreasing in diameter from rear to front, a sheet metal hood appliedagainst the wall of said cavity, said hood having an aperture at therear end thereof, a main detonator located in the explosive loadrearward of the sheet metal hood, a tubular member located in said loadof explosive and extending through the aperture and having its front endcentered in the hood with a front orifice opening into the space in saidhood, said tubular member cooperating with the hood for preventing gasesof the exploded charge from penetrating inside the hood, a sensitivehead fuse located at the front end of the projectile and including apriming detonator having a part extending into the hollow front endpositioned for delivering the flame of detonation into said hollow frontend of said hood, said detonators being held spaced one from the other,said part, front end, hood and tubular member providing means for firetransmission in a direct path from the priming detonator to the maindetonator whereby the space within said hollow front end and said hoodis free of any intervening structure between said part and said tubularmember.

7. In a fuzed projectile, a casing, a main explosive charge within saidcasing and having a forwardly-facing shaped cavity, a detonator indetonating relation with said charge at the rearward end thereof, therebeing an axial passage in said charge extending only from the apex ofsaid cavity to said detonator, an impact fuze, means mounting said fuzein fixed relation with said casing and on the forwardly-extended axis ofsaid charge in spaced relation with said charge, there being a freeuninterrupted space between said impact fuze and said cavity, and meansdirecting the combustion flame of said fuze through said space andthrough said passage to said detonator out of contact with said mainexplosive charge.

8. The projectile in claim 7 wherein said impact fuze includes arearwardly directed shaped cavity.

9. The projectile in claim 7 including a liner for said shaped cavity.

10. The projectile in claim 8 and including a first liner for the shapedcavity of said main charge and a second liner for the shaped cavity ofsaid impact fuze.

11. in a spin stabilized projectile having a cylindrical body and animpact collapsible frusto-conical windshield secured to said body, animpact responsive primer located in the point of said windshield forinitiating action of said projectile upon impact with a target, saidprimer including a first rearwardly directed shaped charge, a secondforwardly opening shaped charge within and coextensive with said body,there being an axial separation between the apices of said shapedcharges, said wind shield, said first and said second shaped chargesdefining a space free of intervening structure, detonating means at thebase of said projectile for detonating said second charge, there beingan elongated axial passage in said second charge and communicating withsaid detonating means, and a kinetic element responsive to thedetonation of said first charge rearwardly projectible through saidspace and to and through said axial passage to initiate action of saiddetonating means.

12. The projectile of claim 11 and including a centrifugally responsiveslide member transversely slidable in a bore formed in said detonatingmeans, a detonator in said slide member integrally movable therewithfrom first safe position to second armed position in axial alinementwith said flash passage, and centrifugally responsive detent means insaid detonating means releasably engaging said slide member, said detentmeans releasable at a predetermined forward speed of said projectile topermit said slide and detonator to move to arming position.

13. The projectile of claim 11 and including a liner for said firstshaped charge, said liner forming said kinetic element when said firstshaped charge is detonated.

14. The projectile of claim 13 and including a centrifugally responsiveslide member transversely slidable in a bore formed in said detonatingmeans, a detonator in said slide member integrally movable therewithfrom first safe position to second armed position in axial alinementwith said flash passage, and centrifugally responsive detent means insaid detonating means releasably engaging said slide member, said detentmeans releasable at a predetermined forward speed of said projectile topermit said slide and detonator to move to arming position.

15. The projectile of claim 11 wherein said kinetic element is the blastpropogated by detonation of said first shaped charge.

16. The projectile of claim 15 and including a centrifugally responsiveslide member transversely slidable in a bore formed in said detonatingmeans, a detonator in said slide member integrally movable therewithfrom first safe position to second armed position in axial alinementwith said flash passage, and centrifugally responsive detent means insaid detonating means releasably engaging said slide member, said detentmeans releasable at a predetermined forward speed of said projectile topermit said slide and detonator to move to arming position.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 633,458 Jared Sept. 19, 1899 1,322,683 Barlow Nov. 18, 19191,534,012 Watson Apr. 14, 1925 1,563,418 Adelman Dec. 1, 1925 1,955,779Teitscheid Apr. 24, 1934 FOREIGN PATENTS N umb er Country Date 28,030Great Britain Dec. 13, 1911 217,955 Great Britain June 24, 1924 467,392Great Britain June 16, 1937 113,685 Australia Aug. 14, 1941

